Apparatus for the control of highway crossing signals



1939. s. R. 'PFLASTERER 2,175, 8

APPARATUS FOR THE CONTROL OF HIGHWAY CROSSING SIGNALS Filed Feb. 23, 1959 INVENTOR Gozyefl f ZQPQP.

BY 5 K HIS ATTORN EY Patented Oct. 10, 1939 UNHTED STATES PATENT O F F I C E APPARATUS FOR THE CONTROL OFQ'HIGH- WAY CROSSINGSIGNALS Application February 23, 1939, Serial No. 257,928

8 Claims.

My invention relates toapparatus for the control of highway'crossing signals, and particularly to apparatus capable ofcontrolling highway crossing signals for a track over which trains operate in both directions, was to continue the operation of the signal when a train enters a control section in approaching the intersection from one direction after the operation of the signal has been initiated by another train entering another control section in approaching the intersection from the other direction, but which other train reverses direction to vacate the other control section.

An object of my invention is the provision, in apparatus of the character described, of novel and improved means effective to maintain operation of highway crossing signals during momentary losses of train shunt within a control section.

Other objects and advantages of my invention will appear as. the specification progresses.

I shall describe one form of apparatus embodying my invention, and shall then point out the novel features thereof in claims.

The accompanying drawing is a diagrammatic view of a preferred form of apparatus embodying my invention.

Referring to the drawing, the reference characters l and la designate the track rails of a stretch of railway track over which traflic moves in both directions, and which is intersected at grade by a highway I-I. Located adjacent the intersection is a highway crossing signal S, which may be of any suitable type, but which, as here shown, is an audible signal in the form of an electric bell.

The track railsl and la are divided by means of the usual insulated rail joints 2 into relatively long outer sections DE and FG separated from each other by a relatively short section E-F. Sections D-E and FG will usually be of: such length suitable to provide an adequate warning period to highway users of the approach of a train to the intersection. Section E--F will usually be of such length as tocompletely include theintersection.

Sections D-E, E-F and FG are provided with track circuits comprising in each instance a suitable source of current, such as track battery 3, connected across the track rails at one end of the section and a track relay, designated by the reference characters ITR, 2TB. and 3TB, respectively, connected across the track rails at the other end.

The reference characters ITPS and 3TPS designate auxiliary relays, one for each track relay ITR and 3TB, respectively, for the outer track sections DE and F-G. Relay lTPS is normally energized over a stick circuit passing from one terminal B of a suitable source of current, such as a battery not shown, through front contact 5 of relay ITR, front contact 8 of relay lTPS, and the windingof relay ITPS to the other terminal C of the source of current. Relay 3TPS is normally energized over a stick circuit passing from terminal Bthrough'front contact l of relay 5TB, front contact 8 of relay 3TPS, and the winding of relay 3TPS to terminal 0. Relay lTPS is provided with a first pick-up circuit which may be traced from terminalB'through back contact 3! of relay 2TB, and the winding of relay I'I'PS to terminal C. Relay 3TPS is provided with a first pick-up circuit passing from terminal B throughback contact 32 of relay 2TB, and the winding of relay 3TPS to terminal C. Relays ITPS and 3TPS are provided each with a second pick-up circuit which will be pointed out hereinafter.

The reference characters ITER and S'IER designate time element relays, one for each track relay ITR and 3TB, respectively. The time element relays ITER. and 3TER may be of any suitable type, such as, for example, the type described in- United States Letters Patent No.- 2,114,895, granted on April 19, 1938, toI-I. E. Ashworth for Thermal relays. These relays are each provided with a normally open contact which closes within a predetermined time interval of, say, 10 seconds after therelay is energized. The circuit for energizingrelay lTER may be tracedfrom terminal B through front contact 5 of relay lTR, the operating element of relay I-IER, and back contact I6 of relay ITPS to terminal C. The circuit for energizing relay 3TER may be traced from, terminal B:through front contact I of relay 3TR, the operating element of relay ETER, and back contact ll of relay STPS to terminal C. Each time element relay ITER. or STER cooperates with its associatedtrack relay to provide the second pick-up circuit for the auxiliary relay iTPS or 3TPS, respectively, andto prevent in a mannerto be described in detail presently, a-momentary loss of train shunt in control section DE or F-G fronreffectingthe operation of signal S. The second pick-up circuit for relay ITPS may be traced from terminal B through front contact 5 of relay ITR, contact I2'of relay ITER, and the winding of relay ITPS to terminal C. The second pick-up circuit for relay 3TPS passes from terminal B throughfront contact I of relay 3TB, contact [3 of relay 3TER, and the winding of relay 3TPS to terminal C.

The reference character CR designates a signal operating relay preferably provided with slightly slow releasing characteristics, for governing the operation of signal S. Relay CR is normally energized over a stick circuit passing from terminal B through front contact I4 of relay ITR, front contact l5 of relay 2TR, front contact l6 of relay 3TB, front contact I! of relay CR and the winding to relay OR to terminal C. A first pick-up circuit for relay GR is governed by each of the track and auxiliary relays, and may be traced from terminal B through front contact 9 of relay ZTR, front contact l8 of relay lTR, front contact IQ of relay ITPS, front contact 29 of relay 3TB, front contact 2| of relay STPS, and the winding of relay CR to terminal C. At times, however, the track relay l TR or STR for the outer track section D-E or FG, and the associated auxiliary relay ITPS or 3TPS, are prevented in a manner to be explained presently from controlling the pick-up circuit for relay CR.

The immediate operating circuit for signal S passes from terminal B through back contact 22 of relay CR, and the winding of signal S to terminal C, so that signal S operates whenever relay CR is released.

The reference characters ISR and 38B designate directional stick relays, one for each of the track relays ITR and 3TR for the outer track sections DE and FG. Relay I SR is provided with a pick-up circuit passing from terminal B through back contact 5 of relay ITR, front contact 23 of relay 3TPS, back contact 24 of relay 38R, and the winding of relay ISR to terminal C. A first stick circuit for relay ISR may be traced from terminal B through back contact 9 of relay ZTR, front contact 25 of relay I SR, and the winding of relay ISR to terminal C; and a second stick circuit for relay ISR passes from terminal B through back contact 1 of relay 3TR, front contact 26 of relay ITPS, front contact 21 of relay ISR, and the winding of relay ISR to terminal C. The relay 38R is provided with a pick-up circuit passing from terminal B through back contact 1 of relay 3TR, front contact 26 of relay ITPS, back contact 27 of relay ISR, and the winding of relay 38R to terminal C. A first stick circuit for relay 38R passes from terminal B through back contact 9 of relay 2TR, front contact 28 of relay 33R, and the winding of relay 35R to terminal C; while a second stick circuit for relay 38R passes from terminal B through back contact 5 of relay ITR, front contact 23 of relay 3TPS, front contact 24 of relay 38R and the winding of relay 38R to terminal C. When energized, relay ISR or 3SR prevents relays 3TR and 3TPS, or relays ITR and I'IPS, respectively, from controlling the pick-up circuit for relay CR, by providing an alternate path around the control contacts of those relays interposed in the pick-up circuit for relay CR. That is to say, when relay ISR is picked up to close front contact 29 a path is established around front contact 20 of relay 3TR and front contact 2| of relay 3TPS, which contacts as pointed out previously are normally included in the pick-up circuit for relay CR, the pick-up circuit for the operating relay OR in this latter event including front contact 9 of relay ZTR, front contact l8 of relay ITR, front contact I9 of relay ITPS, then front contact 29 of relay ISR, and the winding of relay CR. When relay 38B is energized to close its front contact 30, an alternate path is established around front contact l8 of relay l TR and front contact l9 of relay ITPS, which contacts are normally included in the pick-up circuit for relay CR. The pick-up circuit for relay CR in this latter event includes front contact 9 of relay ZTR, front contact 30 of relay 3SR, front contact 20 of relay 3TR, front contact 2| of relay STPS, and the winding of relay CR. These alternate paths provided by relays ISR and 3SR, as will be explained in detail presently, cooperate with the track relays ITR, ZTR and STR to provide directional control of signal S, whereby relay ISR or 35R, as the case may be, prevents trains operating in the eastbound or westbound direction, respectively, from controlling the signal after such trains have crossed the intersection and vacated section E- F.

The apparatus is in its normal condition, as shown in the drawing when no trains are operating on the stretch of railway track intermediate the points D and G. In this normal condition of the apparatus, the relays ITR, ZTR, 3TR, ITPS, 3TPS and CR are energized, and the relays iTER, 3'IER, ISR, 35R and signal S are deenergized.

Having thus described the apparatus embodying my invention, I shall first explain the operation of the apparatus for a train which enters an outer section in approaching the intersection and continues to operate in the same direction so that it crosses the intersection and passes through the other outer control section. Assuming, for example, that an eastbound train, that is, a train operating from left to right in the drawing, enters section D-E in approaching the intersection, then relay ITR is shunted and releases to open front contacts 5, l4 and I8, and to close its back contact 5. The opening of front contacts l4 and I8 opens respectively the stick and pick-up circuits for relay CR, with the result that relay CR releases to close its back contact 22, thereby initiating the operation of signal S, which now exhibits its warning indication to highway users of the approach of the train. The opening of front contact 5 of relay I TR opens the stick circuit for auxiliary relay ITPS, with the result that relay ITPS releases to open its front contact l9 interposed in the pick-up circuit for relay CR, and the closing of back contact 5 of relay ITR completes the previously traced pickup circuit for stick relay ISR, whereupon relay ISR becomes energized to close its front contact 29.

In the event a momentary loss of train shunt occurs while the train occupies section DE, the track relay ITR might pick up, following the fluctuation in the train shunt, but the operation of the control device, that is, signal S is unaffected, since relay ITR ordinarily will release prior to relay ITPS picking up to complete the pick-up circuit for relay CR. That is to say, if relay ITR picks up on a momentary loss of shunt in section DE, to close at front contact 5 the energizing circuit for relay ITER, relay ITER must be energized for its predetermined time interval before contact [2 of relay ITER is closed. When contact l2 of relay ITER is closed, and in the event that relay ITR is not released due to the restoration of the train shunt in section D-E, then the previously traced second pick-up circuit for relay ITPS is established, with the result that relay I TPS picks up to close front contact l9 and thereby complete the pick-up circuit for the operating relay CR. However, relay ITR remainremote possibility, since ordinarily a loss of train' shunt within a control section is of very few seconds in duration, so that the train shunt is normally restored and relay ITR released prior to the pick-up circuit for relay CR being completed, with the result that the operation of signal S is unaffected by the picking up and releasing of relay ITR in response to variations in train shunt in the control section. It should be pointed out that relay ISR- might bealternately energized and deenergized in step with the picking up and releasing of the relay ITR in response to the varying train shunt, but this operation of relay ISR at this time is immaterial.

When the eastbound train enters section EF, relay 2TR is shunted and-releases to open front contact Swhich is interposed in the pick-up circuit" for relay CR, and to close back contacts 9, 3| and 32. The closing of back contact 9 of relay 2TR completes the previously traced first stick circuit for relay ISR, so that relay ISR is maintained energized over its first stick circuit While the train occupies section E-F. Relay 2TR also completes at its back contacts 3| and 32, respectively, the first pick-up circuit for relay ITPS and 3TPS, with the-result that relay I'IPS is energized and closes front contacts 6, l9 and 26 interposedrespectively in the stick circuit for relay ITPS, the'pick-up circuit for relay CR, and the second-stick circuit for relay |SR.

When the train enters section F-G, relay 3TR releases to close its back contact '1, thereby completing the second stick circuit for relay ISR, and to Open the stick -circuit'for relay 3'I'PS at front contact I. Relay STPS, however, remains energized over its previously traced first pick-up circuit including back contact 32 of relay 2TR. Front contacts l6 and 20 of relay 3TR interposed respectively in the stick and pick-up circuits for relay CR, are also opened when relay 3TR releases.

When the train vacates section D-E, relay ITR picks up to close front contact |8 interposed in-the pick-up circuit for relay CR to prepare that circuit, and to close at front contact 5 of relay |TR the stick circuit for relay ITPS. With relays ITR, ITPS and ISR energized, the operation of signal S is maintained while the train occupies section E-F by virtue of the fact that relay 2TR is released and holds open front contact 9, which is interposed in the pick-up circuit for relay CR. 1

When the train vacates section E-F, relay 2TR picksup to close front contact 9, thereby completing the pick-up circuit for relay CR including front contact 29 of relay ISR, with the result that relay CR picks up and opens at its back contact 22 the operating circuit for signal S and signal S now ceases to displayits warning indication to highway users. Relay 2TR also opens its back contact 32 to open the first pick-up circuit for relay 3TPS, with the result that relay STPS releases to open its front contact 2| interposed in the pick-up circuit for relay CR, but as was pointed out hereinbefore, the pick-up circuit for relay CR is provided with an alternate path around front contact 2| of relay 3TPS and front contact 2|] of relay 3TR, which alternate path includes closed front contact 29 of relay ISR.

With relay ISR energized over its second stick circuit including front contact 26 of relay ITPS and backxcontact lof relay 3TR, it is obvious that relay ISR is maintained energized'while the. train occupies section.F-G, with the result'that relays 3TR and STPS are removed from control of signal control relay CR and of signal S. It follows that with relay ISR energized, a train occupying section F--G in recedingfrom the intersection is prevented from effecting the operation of signal S.

When the train vacates section F-G, relay 3TR picks up to close front contacts I6 and-20 interposed respectively in the stick and pick-up circuitsfor relay CR, to open its back contact I, and to close its front contact I. The opening of back contact 1 of relay 3TR opens the second stick circuit for relay ISR, with the result that relay ISR releases to open its front contact 29 included in the alternate path in the pick-up circuit for relay CR around front contact 2| of relay STPS, which contact is still open. Relay CR, as was pointed out previously, is slightly slow releasing so that front contact IB of relay 3TB closes to complete the stick circuit for relay CR prior to relay CR releasing and opening its front contact I! interposed in this stick circuit'for relay CR, with the result that relay CR remains energized to prevent operation of signal S. With front contact I of relay 3TR and back contact ll of relay 3TPS closed, the previously traced circuit for energizing relay 2TER is completed whereupon relay 3TER at the end of its predetermined time interval closes its contact l3 to complete the second pick-up circuit for relay STPS. Relay 3TPS now picks up to close its front contacts 8 and 2| interposed respectively in the stick circuit for relay 3TPS and the pick-up. circuit for relay CR, and to open at its back contact H the energizing circuit for relay 3TER, which becomes deenergized to open its contact 3. The apparatus is now restored to its normal condition.

I shall now explain the operation of the apparatus embodying my invention for a train which enters an outer control section in approaching the intersection after another train has entered the other outer control section in approaching the intersection, but which other train reverses its direction and vacates the associated outer control section. Assuming that a westbound train, that is, a train operating from right to left in the drawing, first enters section F-G in approaching the intersection, relay 3TR is shunted and releases to open front contacts I, I6 and 20. The opening of front contacts l6 and 2B interposed respectively in the stick and pick-up circuits of relay CR, results in relay CR releasing to complete the operating circuit for signal S, whereupon the operation of signal S is initiated. The opening of front contact I of relay 3TR opens the previously traced stick circuit for relay BTPS, with the result that relay 3TPS releases to open its front contact 2| interposed in the pick-up circuit'for relay CR, while the closing of back contact of relay 3TR completes the pick-up circuit for relay 38R, whereupon relay 3SR picks up to close front contact 30.

Then, when an eastbound train enters section DE in approaching the intersection, relays ITR and ITPS become released to open respectively front contacts Hi and I9 interposed in the pick-up circuit for relay CR, and relay ITPS also opens front contact 26 interposed in the pick-up circuit for relay 38R whereupon relay 3SR releases, so that relay 3SR no longer provides an alternate path including its front contact 30 around contacts l8 and IQ of relays lTRandITPS interposed in the pick-up circuit for relay CR. With the pick-up circuit for relay CR opened at front contacts l8 and IQ of relays ITR and ITPS, it follows that when the westbound train reverses direction in section F- G and vacates section F-G at its right-hand end, so that relay 3TB. immediately picks up to close its front contact 2|] interposed in the pick-up circuit for relay CR, and relay 3TPS is caused to pick up, as will be explained hereinafter, to close its front contact 2| interposed in the pick-up circuit for relay CR, the operation of relay CR and of signal S is not affected, and the second train maintains the operation of the signal S which has been initiated by the first or westbound train entering the other control section F-G. Thus, when the westbound train backs out of section F--G and relay 3TB closes its front contact as pointed out above, relay 3TR also closes at its front contact I the energizing circuit for relay 3TER. At the end of its predetermined time interval, relay 3TER closes its contact 13 with the result that the second pick-up circuit for relay STPS is completed whereupon relay 3'I'PS picks up to close front contacts 2| and 23 interposed respectively in the pick-up circuits for relay CR and relay ISR. With front contact 23 of relay 3TPS and back contact 5 of relay ITR. closed, relay [SR picks up to close its front contact 29. The apparatus is now conditioned by the presence of the train in section DE, to maintain operation of the signal S for further operation of the train until that train clears the intersection and vacates section E-F, and to prevent operation of the signal while the train recedes from the intersection through the outer section FG, in the manner described in detail previously for the operation of the apparatus for an eastbound train.

The operation of the apparatus embodying my invention for a westbound train operating across the intersection and through the outer section D-E on the other side of the intersection is substantially similar to the operation previously described for an eastbound train, and it is believed, therefore, that this latter operation will be readily apparent from the foregoing description together with an inspection of the drawing without further detailed explanation.

Alhough I have herein shown and described only one form of apparatus embodying my invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. In combination, a stretch of railway track divided into two outer sections and an intermediate section, said intermediate section being intersected by a highway and provided with a highway crossing signal located at such intersection, a track circuit including a track relay for each section, two auxiliary relays one for each track relay for the outer sections, operating means governed jointly by said track relays and by said auxiliary relays for causing said signal to operate for railway traffic moving in either direction in said intermediate section but to operate for railway traffic moving only toward the intersection in said two outer sections, and means governed by each track relay for the outer sections for controlling the associated auxiliary relay to prevent a momentary loss of train shunt in an outer section from effecting loss of operation of said signal.

2. In combination, a stretch of railway track divided into two outer sections and an intermediate section, said intermediate section being intersected by a highway and provided with a highway crossing signal located at such intersection, a track circuit including a track relay for each section, two auxiliary relays one for each track relay for the outer sections, operating means governed jointly by said track relays and by said auxiliary relays for causing said signal to operate for railway traflic moving in either direction in said intermediate section but to operate for railway trafiic moving only toward the intersection in said two outer sections, two time element relays one for each auin'liary relay, means for controlling each of said time element relays governed by its associated auxiliary relay and the track relay associated therewith, and means governed by each time element relay for preventing a loss of train shunt within its associated outer section from effecting loss of operation of said signal.

3. In combination, a stretch of railway track divided into three sections, a track relay for each section, a signal, a signal operating relay normally energized over a stick circuit including a front contact of each of said track relays, two auxiliary relays one associated with each of two of said track relays, a pick-up circuit for said signal operating relay including a front contact of each of said track relays and a front contact of each of said auxiliary relays, and means governed by each of said two track relays for controlling its associated auxiliary relay to prevent a momentary loss of train shunt in the section for that track relay from effecting loss of operation of said signal.

4. In combination, a stretch of railway track divided into three sections, a track relay for each section, two auxiliary relays one associated with each of two of said track relays and each auxiliary relay normally energized over a stick circuit including a front contact of its associated track relay, two time element relays one for each auxiliary relay, an energizing circuit for each time element relay including a back contact of its associated auxiliary relay and a front contact of the track relay associated therewith, a pick-up circuit for each auxiliary relay including a front contact of its associated track relay and a contact of its associated time element relay closed in a predetermined period after energization thereof, a signal, a signal operating relay, circuit means for controlling said signal operating relay including a front contact of each of said track relays and a front contact of each of said auxiliary relays, and two directional stick relays one for each direction and controlled by said two track relays for at times preventing the associated track relay from controlling said signal operating relay.

5. In combination, a stretch of railway track divided into three sections, a track relay for each section, two auxiliary relays one associated with each of two of said track relays and each auxil iary relay normally energized over a stick circuit including a front contact of its associated track relay, two time element relays one for each auxiliary relay, an energizing circuit for each time element relay including a back contact of its associated auxiliary relay and a front contact of the track relay associated therewith, a pick-up circuit for each auxiliary relay including a front contact of its associated track relay and a contact of its associated time element relay closed in a predetermined period after energization thereof, a signal, a signal operating relay normally energized over a stick circuit including a front contact of each of said track relays, a pick-up circuit for said signal operating relay including a front contact of each of said track relays and a front contact of each of said auxiliary relays, and two directional stick relays one for each direction and controlled by said two trackrelays for at times preventing the associated track relay and its associated auxiliary relay from controlling the pick-up circuit for said signal operating relay.

6. In combination, a stretch of railway track divided into three sections, a track relay for each section, two auxiliary relays one associated with each of two of said track relays and each auxiliary relay normally energized over a stick circuit including a front contact of its associated track relay, two time element relays one for each auxiliary relay, an energizing circuit for each time element relay including a back contact of its associated auxiliary relay and a front contact of the track relay associated therewith, a pick-up circuit for each auxiliary relay including a front contact of its associated track relay and a contact of its associated time element relay closed in a' predetermined period after energization thereof, a signal, a signal operating relay, circuit means for controlling said signal operating relay including a front contact of each of said track relays and a front contact of each of said auxiliary relays, two directional stick relays one for each direction and controlled by said two track relays for at times preventing the associated track relay from controlling said signal operating relay, and other circuit means for controlling said signal operating relay including a front contact of each of said track relays.

'7. In combination, a stretch of railway track divided into three sections, a track relay for each section, two auxiliary relays one associated with each of two of said track relays and each auxiliary relay normally energized over a stick circuit including a front contact of its associated track relay, a first pick-up circuit for each auxiliary relay governed by the third one of said track relays, two time element relays one for each auxiliary relay, an energizing circuit for each time element relay governed by a back contact of its associated auxiliary relay and a front contact of the track relay associated therewith, a second pick-up circuit for each auxiliary relay including a front contact of the associated track relay and a contact of the associated time ele ment relay closed in a predetermined period after energization thereof, a signal, a signal operating relay, circuit means for controlling said signal operating relay governed by a front contact of each of said track relays and by a front contact of each of said auxiliary relays, and two directional stick relays one for each direction and controlled by said two track relays for at times preventing the associated track relay from controlling said signal operating relay.

8. In combination, a stretch of railway track divided into three sections, a track relay for each section, a signal, a signal operating relay normally energized over a stick circuit including a front contact of each of said track relays, two auxiliary relays one associated with each of two of said track relays and each auxiliary relay normally energized over a stick circuit including a front contact of its associated track relay, a first pick-up circuit for each auxiliary relay governed by the third one of said track relays, a pick-up circuit for said signal operating relay governed by a front contact of each of said track relays and auxiliary by a front contact of each of said relays, two directional stick relays one for each direction and controlled by said two track relays for at times rendering the associated track relay and its associated auxiliary relay ineffective to govern the pick-up circuit for said signal operating relay, two time element relays one for each of said auxiliary relays, an energizing circuit for each time element relay including a back contact of its associated auxiliary relay and a front contact of the track relay associated therewith, and a second pick-up circuit for each auxiliary relay including a contact of its associated time element relay closed in a predetermined period after energization thereof, whereby the picking up of a track relay in response to a loss of shunt within its control section is ineffective to govern the pickup circuit for said signal operating relay.

GEORGE R. PFLASTERER.

CERTIFICATE OF' CORRECTION. Patent No. 2,175,1 08. October 10, 19 9.

- GEORGE R. PFLASTERER. It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as-followsz Page 5, second column, line 50, claim 8, strike out the Word "auxiliary" and insert the same after "said" in line 51, same claim; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

sigled and sealed this llith day of November, A. D. 1959.

Henry Van Arsdale (Seal) Acting Commissioner of Patents. 

